About 1.6 million people in the USA alone are confined to wheelchairs that serve as their only means of mobility. As a result, their lives are full of endless obstacles such as stairs, rugged pavement and narrow passages. Furthermore, lack in standing position for long periods of time and having only limited upper-body movements, often inflict hazardous health complications. In order to prevent rapid health deterioration, expensive equipment such as standing frames and trainers must be used in addition to ample physio/hydro-therapy.
Functional Electrical Stimulation (FES) is a known method in which electrodes are attached to various bodily parts (legs and thighs) and electrical pulses are applied to the muscles in order to invoke muscles motion and consequently impose a gait. The use of FES is discussed by Kralj, A. in “Gait Restoration in Paraplegic Patients: A Feasibility Demonstration Using Multichannel Surface Electrodes FES”, J. Rehab. Res. Dev., vol. 20, pp. 3–20 (1983). In this method, choosing the proper parameters for the pulse sequences (amplitude, shape, frequency and timing) and real-time adapting these parameters along the gait are of the main research areas of that field. While FES is a true muscle-based walking, the main disadvantage of this method is in the fact that it does not provide an effortless usage and an efficient restoration of functional daily activities.
An Example of an approach that addresses the problem of gait restoration is disclosed in U.S. Pat. No. 4,422,453 “External Apparatus for Vertical Stance and Walking for those with Handicapped Motor Systems of the Lower Limbs” by Salort and filed in 1982. In this patent, a corset and girdles are attached to the body. The harness contains strips of flexible metal capable of absorbing and restoring the flexural and torsonal stresses. The locomotive force in this case is bodily based and is actually a reciprocal gait orthosis (RGO), which is a walk-assisting device, that does not provide a practical daily solution to the handicapped person. Other examples of RGO devices are disclosed in U.S. Pat. No. 5,961,476 “Walk Assisting Apparatus” by Betto et al., filed in 1997 and U.S. Pat. No. 4,946,156 by Hart, filed in 1988. The first patent by Betto discloses a walk assisting apparatus that comprises full leg brace for both legs interconnected by links to the coxa so as to provide leg supports to make the alternate walk properly. The later patent by Hart discloses a reciprocation gait orthosis that comprises hip joints coupled to a push/pull member, which is thigh fit, as well as two limb members.
In general, the RGO are non-motorized brace systems that are wore by the user, while the user himself performs the locomotion. Any type from the available RGO is better fitted as a trainer than a functional walking aid.
Motorized bracing system is disclosed in U.S. Pat. No. 5,961,541 “Orthopedic Apparatus for Walking and Rehabilitating Disabled Persons Including Tetraplegic Persons and for Facilitating and Stimulating the Revival of Comatose Patients through the Use of Electronic and Virtual Reality Units” by Farrati, filed in 1998. This patent discloses an exoskeleton for the support of a patient's body that is jointed opposite the hip and knee articulations, and is provided with a number of small actuators that are designed to move jointed parts of the exoskeleton in accordance with the human gait. Though the bracing system is motorized, it is a therapeutic device that is not intended for daily functional locomotive activities. The apparatus is confined along a rail or a conveyor, where the user is not involved in the walking process beyond starting and stopping the gait.
Another locomotion aid, a self-contained electronically controlled dynamic knee-brace system, which aim to add a flexion to knee orthosis is disclosed by Irby et al. in “Automatic Control Design for a Dynamic Knee-Brace System”, IEEE Trans. Rehab. Eng., vol. 7, pp. 135–139 (1999).
All the above discussed rehabilitation devices for disabled persons confined to wheelchairs as well as available devices in rehabilitation institutions are used for training purposes only. A solution that enables daily independent activities that restore the dignity of handicapped persons, dramatically ease their lives, extend their life expectancies and reduce medical and other related expenses is so far not available.